Older adults, who are frail are twice more likely to experience delirium following a surgery, a study found.

Delirium is a serious disturbance in mental abilities that results in confused thinking and reduced awareness of your environment. The researchers noted that frailty and cognitive impairment are the risk factors most strongly associated with the development of postoperative delirium.

Other risk factors that are associated with developing postoperative delirium include smoking and the use of psychotropic medications. Previous researches found that frailty and cognitive impairment before surgery are associated with developing complications after surgery, but age is not.

“Chronological age from your birth date is not always an accurate assessment of how you’ve aged over your lifetime,” said Jennifer Watt, a geriatric medicine fellow at St. Michael Hospital in Canada.

“This study highlights how common delirium is among older adults undergoing elective surgery, and the importance of geriatric syndromes, including frailty, in identifying older adults who may be at risk,” Watt added.

For the study, published in the Journal of General Internal Medicine, the researchers reviewed 41 existing studies including more than 9,000 patients 60 years and older and reporting on postoperative delirium following an elective surgery.

The results showed that one in six older adults experience delirium following an elective surgery. Patients who developed delirium following elective surgery are also at an increased risk of developing other adverse postsurgical outcomes, and are more likely to be discharged to a long-term care facility, or die following surgery, according to the review.